Originally Posted by
mcours2006
Get Ultegra and put the $500 toward a set of wheels.
+1
And since the OP is getting disc brakes, he can run wheels with carbon rims as well. But many of those will be over the $500 mark, though. In that case, you could sell off the OEM wheels to make up some of the cost difference. If not wheels, then aerobar, stem, different seatpost, clothing, helmet, shoes and pedals, etc...